#pragma once

#include <string>
#include <vector>

#include "Utilities/StrUtil.h"
#include "util/types.hpp"

#include <unordered_map>

enum class FUNCTION
{
	NOP,
	DP2,
	DP2A,
	DP3,
	DP4,
	DPH,
	SFL, // Set zero
	STR, // Set One
	FRACT,
	DFDX,
	DFDY,
	REFL,

	// Samplers. Must be clustered in order 1D-2D-3D; CUBE maps as a 3D texture here
	TEXTURE_SAMPLE_BASE,
	TEXTURE_SAMPLE_BIAS_BASE,
	TEXTURE_SAMPLE_PROJ_BASE,
	TEXTURE_SAMPLE_LOD_BASE,
	TEXTURE_SAMPLE_GRAD_BASE,
	TEXTURE_SAMPLE_SHADOW_BASE,
	TEXTURE_SAMPLE_SHADOW_PROJ_BASE,
	TEXTURE_SAMPLE_DEPTH_RGBA_BASE,
	TEXTURE_SAMPLE_DEPTH_RGBA_PROJ_BASE,

	TEXTURE_SAMPLE1D,
	TEXTURE_SAMPLE1D_BIAS,
	TEXTURE_SAMPLE1D_PROJ,
	TEXTURE_SAMPLE1D_LOD,
	TEXTURE_SAMPLE1D_GRAD,
	TEXTURE_SAMPLE1D_SHADOW,
	TEXTURE_SAMPLE1D_SHADOW_PROJ,
	TEXTURE_SAMPLE1D_DEPTH_RGBA,
	TEXTURE_SAMPLE1D_DEPTH_RGBA_PROJ,

	TEXTURE_SAMPLE2D,
	TEXTURE_SAMPLE2D_BIAS,
	TEXTURE_SAMPLE2D_PROJ,
	TEXTURE_SAMPLE2D_LOD,
	TEXTURE_SAMPLE2D_GRAD,
	TEXTURE_SAMPLE2D_SHADOW,
	TEXTURE_SAMPLE2D_SHADOW_PROJ,
	TEXTURE_SAMPLE2D_DEPTH_RGBA,
	TEXTURE_SAMPLE2D_DEPTH_RGBA_PROJ,

	TEXTURE_SAMPLE3D,
	TEXTURE_SAMPLE3D_BIAS,
	TEXTURE_SAMPLE3D_PROJ,
	TEXTURE_SAMPLE3D_LOD,
	TEXTURE_SAMPLE3D_GRAD,
	TEXTURE_SAMPLE3D_SHADOW,
	TEXTURE_SAMPLE3D_SHADOW_PROJ,
	TEXTURE_SAMPLE3D_DEPTH_RGBA,
	TEXTURE_SAMPLE3D_DEPTH_RGBA_PROJ,

	TEXTURE_SAMPLE2DMS,
	TEXTURE_SAMPLE2DMS_BIAS,
	TEXTURE_SAMPLE2DMS_PROJ,
	TEXTURE_SAMPLE2DMS_LOD,
	TEXTURE_SAMPLE2DMS_GRAD,
	TEXTURE_SAMPLE2DMS_SHADOW,
	TEXTURE_SAMPLE2DMS_SHADOW_PROJ,
	TEXTURE_SAMPLE2DMS_DEPTH_RGBA,
	TEXTURE_SAMPLE2DMS_DEPTH_RGBA_PROJ,

	VERTEX_TEXTURE_FETCH1D,
	VERTEX_TEXTURE_FETCH2D,
	VERTEX_TEXTURE_FETCH3D,
	VERTEX_TEXTURE_FETCHCUBE,
	VERTEX_TEXTURE_FETCH2DMS,

	// Meta
	TEXTURE_SAMPLE_MAX_BASE_ENUM = TEXTURE_SAMPLE_DEPTH_RGBA_PROJ_BASE, // Update if more base enums are added
	TEXTURE_SAMPLE_BASE_ENUM_COUNT = (TEXTURE_SAMPLE_MAX_BASE_ENUM - TEXTURE_SAMPLE_BASE + 1),
};

enum class COMPARE
{
	SEQ,
	SGE,
	SGT,
	SLE,
	SLT,
	SNE,
};

enum ParamFlag
{
	PF_PARAM_IN,
	PF_PARAM_OUT,
	PF_PARAM_UNIFORM,
	PF_PARAM_CONST,
	PF_PARAM_NONE,
	PF_PARAM_COUNT,
};

struct ParamItem
{
	const std::string name;
	const std::string value;
	int location;

	ParamItem(std::string _name, int _location, std::string _value = "")
		: name(std::move(_name))
		, value(std::move(_value)),
		location(_location)
	{ }
};

struct ParamType
{
	const ParamFlag flag;
	const std::string type;
	std::vector<ParamItem> items;

	ParamType(const ParamFlag _flag, std::string _type)
		: flag(_flag)
		, type(std::move(_type))
	{
	}

	bool HasItem(const std::string& name) const
	{
		return std::any_of(items.cbegin(), items.cend(), [&name](const auto& item)
		{
			return item.name == name;
		});
	}

	bool ReplaceOrInsert(const std::string& name, const ParamItem& item)
	{
		if (HasItem(name))
		{
			std::vector<ParamItem> new_list;
			for (const auto& it : items)
			{
				if (it.name != name)
				{
					new_list.emplace_back(it.name, it.location, it.value);
				}
				else
				{
					new_list.emplace_back(item.name, item.location, item.value);
				}
			}

			std::swap(items, new_list);
			return true;
		}

		items.push_back(item);
		return false;
	}
};

struct ParamArray
{
	std::vector<ParamType> params[PF_PARAM_COUNT];

	ParamType* SearchParam(const ParamFlag &flag, const std::string& type)
	{
		for (auto& param : params[flag])
		{
			if (param.type == type)
				return &param;
		}

		return nullptr;
	}

	bool HasParamTypeless(const ParamFlag flag, const std::string& name) const
	{
		const auto& p = params[flag];
		return std::any_of(p.cbegin(), p.cend(), [&name](const auto& param)
		{
			return param.HasItem(name);
		});
	}

	bool HasParam(const ParamFlag flag, const std::string& type, const std::string& name)
	{
		const ParamType* t = SearchParam(flag, type);
		return t && t->HasItem(name);
	}

	std::string AddParam(const ParamFlag flag, const std::string& type, const std::string& name, const std::string& value)
	{
		ParamType* t = SearchParam(flag, type);

		if (t)
		{
			if (!t->HasItem(name)) t->items.emplace_back(name, -1, value);
		}
		else
		{
			params[flag].emplace_back(flag, type);
			params[flag].back().items.emplace_back(name, -1, value);
		}

		return name;
	}

	std::string AddParam(const ParamFlag flag, const std::string& type, const std::string& name, int location = -1)
	{
		ParamType* t = SearchParam(flag, type);

		if (t)
		{
			if (!t->HasItem(name)) t->items.emplace_back(name, location);
		}
		else
		{
			params[flag].emplace_back(flag, type);
			params[flag].back().items.emplace_back(name, location);
		}

		return name;
	}

	void Clear()
	{
		for (auto& param : params)
		{
			param.clear();
		}
	}
};

class ShaderVariable
{
public:
	std::string name;
	std::vector<std::string> swizzles;

	ShaderVariable() = default;
	ShaderVariable(std::string_view var)
	{
		// Separate 'double destination' variables 'X=Y=SRC'
		std::string_view simple_var;
		const auto eq_pos = var.find('=');

		if (eq_pos != umax)
		{
			simple_var = var.substr(0, eq_pos - 1);
		}
		else
		{
			simple_var = var;
		}

		const auto brace_pos = var.find_last_of(')');
		std::string prefix;
		if (brace_pos != umax)
		{
			prefix = simple_var.substr(0, brace_pos);
			simple_var = simple_var.substr(brace_pos);
		}

		const auto var_blocks = fmt::split_sv(simple_var, { "." });

		ensure((!var_blocks.empty()));

		name = prefix + std::string(var_blocks[0]);

		if (var_blocks.size() == 1)
		{
			swizzles.emplace_back("xyzw");
		}
		else
		{
			swizzles = std::vector<std::string>(var_blocks.begin() + 1, var_blocks.end());
		}
	}

	usz get_vector_size() const
	{
		return swizzles[swizzles.size() - 1].length();
	}

	ShaderVariable& simplify()
	{
		std::unordered_map<char, char> swizzle;

		static std::unordered_map<uint, char> pos_to_swizzle =
		{
			{ 0, 'x' },
			{ 1, 'y' },
			{ 2, 'z' },
			{ 3, 'w' }
		};

		for (const auto& p : pos_to_swizzle)
		{
			swizzle[p.second] = swizzles[0].length() > p.first ? swizzles[0][p.first] : 0;
		}

		for (uint i = 1; i < swizzles.size(); ++i)
		{
			std::unordered_map<char, char> new_swizzle;

			for (const auto& p : pos_to_swizzle)
			{
				new_swizzle[p.second] = swizzle[swizzles[i].length() <= p.first ? '\0' : swizzles[i][p.first]];
			}

			swizzle = new_swizzle;
		}

		swizzles.clear();
		std::string new_swizzle;

		for (const auto& p : pos_to_swizzle)
		{
			if (swizzle[p.second] != '\0')
				new_swizzle += swizzle[p.second];
		}

		swizzles.push_back(new_swizzle);

		return *this;
	}

	std::string get() const
	{
		if (swizzles.size() == 1 && swizzles[0] == "xyzw")
		{
			return name;
		}

		return name + "." + fmt::merge({ swizzles }, ".");
	}

	std::string match_size(const std::string& other_var) const
	{
		// Make other_var the same vector length as this var
		ShaderVariable other(other_var);
		const auto this_size = get_vector_size();
		const auto other_size = other.get_vector_size();

		if (this_size == other_size) [[likely]]
		{
			return other_var;
		}

		if (this_size < other_size) [[likely]]
		{
			switch (this_size)
			{
			case 0:
			case 4:
				return other_var;
			case 1:
				return other_var + ".x";
			case 2:
				return other_var + ".xy";
			case 3:
				return other_var + ".xyz";
			default:
				fmt::throw_exception("Unreachable");
			}
		}
		else
		{
			auto remaining = this_size - other_size;
			std::string result = other_var;

			while (remaining--) result += "x";
			return result;
		}
	}

	std::string add_mask(const std::string& other_var) const
	{
		if (swizzles.back() != "xyzw")
		{
			return other_var + "." + swizzles.back();
		}

		return other_var;
	}
};

struct vertex_reg_info
{
	enum mask_test_type : u8
	{
		any = 0,   // Any bit set
		none = 1,  // No bits set
		all = 2,   // All bits set
		xall = 3   // Some bits set
	};

	std::string name;           // output name
	bool need_declare;          // needs explicit declaration as output (not language in-built)
	std::string src_reg;        // reg to get data from
	std::string src_reg_mask;   // input swizzle mask
	bool need_cast;             // needs casting
	std::string cond;           // update on condition
	std::string default_val;    // fallback value on cond fail
	std::string dst_alias;      // output name override
	bool check_mask;            // check program output control mask for this output
	u32  check_mask_value;      // program output control mask for testing

	mask_test_type check_flags; // whole mask must match

	bool test(u32 mask) const
	{
		if (!check_mask)
			return true;

		const u32 val = (mask & check_mask_value);
		switch (check_flags)
		{
		case none:
			return (val == 0);
		case any:
			return (val != 0);
		case all:
			return (val == check_mask_value);
		case xall:
			return (val && val != check_mask_value);
		default:
			fmt::throw_exception("Unreachable");
		}
	}

	bool declare(u32 mask) const
	{
		return test(mask);
	}
};
